Merriam Woods, Missouri has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.3 °C (low) to 20.5 °C (high). Annual precipitation averages 1175.5 Millimeters. Merriam Woods is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.4 °C | 7.6 °C | 70.87 mm |
| February | -2.7 °C | 10.2 °C | 65.28 mm |
| March | 1.5 °C | 15.3 °C | 106.93 mm |
| April | 6.5 °C | 20.8 °C | 132.33 mm |
| May | 11.9 °C | 25.1 °C | 133.6 mm |
| June | 16.9 °C | 29.7 °C | 108.71 mm |
| July | 18.9 °C | 32 °C | 102.36 mm |
| August | 18.2 °C | 31.7 °C | 78.23 mm |
| September | 13.9 °C | 27.7 °C | 113.79 mm |
| October | 7.3 °C | 21.6 °C | 95 mm |
| November | 1.7 °C | 14.9 °C | 99.82 mm |
| December | -2.7 °C | 9.2 °C | 68.58 mm |
| Annual | 7.3 °C | 20.5 °C | 1175.5 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |